From: Matthew Garrett <matthew.garrett@nebula.com> To: Greg KH <gregkh@linuxfoundation.org> Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>, "keescook@chromium.org" <keescook@chromium.org>, "hpa@zytor.com" <hpa@zytor.com> Subject: Re: [PATCH V3 08/11] kexec: Disable at runtime if the kernel enforces module loading restrictions Date: Sun, 8 Sep 2013 14:40:04 +0000 [thread overview] Message-ID: <1378651204.2300.7.camel@x230> (raw) In-Reply-To: <20130908072408.GA5092@kroah.com> [-- Warning: decoded text below may be mangled, UTF-8 assumed --] [-- Attachment #1: Type: text/plain; charset="utf-8", Size: 625 bytes --] On Sun, 2013-09-08 at 00:24 -0700, Greg KH wrote: > On Sun, Sep 08, 2013 at 06:44:08AM +0000, Matthew Garrett wrote: > > At the most trivial level, grab the address of sig_enforce from > > kallsyms, jump to a kernel that doesn't enforce STRICT_DEVMEM, modify > > sig_enforce, jump back to the old kernel. > > Which proves what? sig_enforce can be set, but once it's set can't be unset. Why do you think that is? -- Matthew Garrett <matthew.garrett@nebula.com> ÿôèº{.nÇ+·®+%Ëÿ±éݶ\x17¥wÿº{.nÇ+·¥{±þG«éÿ{ayº\x1dÊÚë,j\a¢f£¢·hïêÿêçz_è®\x03(éÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?¨èÚ&£ø§~á¶iOæ¬z·vØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?I¥
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Garrett <matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org> To: Greg KH <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org> Cc: "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org" <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>, "hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org> Subject: Re: [PATCH V3 08/11] kexec: Disable at runtime if the kernel enforces module loading restrictions Date: Sun, 8 Sep 2013 14:40:04 +0000 [thread overview] Message-ID: <1378651204.2300.7.camel@x230> (raw) In-Reply-To: <20130908072408.GA5092-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org> On Sun, 2013-09-08 at 00:24 -0700, Greg KH wrote: > On Sun, Sep 08, 2013 at 06:44:08AM +0000, Matthew Garrett wrote: > > At the most trivial level, grab the address of sig_enforce from > > kallsyms, jump to a kernel that doesn't enforce STRICT_DEVMEM, modify > > sig_enforce, jump back to the old kernel. > > Which proves what? sig_enforce can be set, but once it's set can't be unset. Why do you think that is? -- Matthew Garrett <matthew.garrett@nebula.com>
next prev parent reply other threads:[~2013-09-08 14:40 UTC|newest] Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-09-03 23:50 Matthew Garrett 2013-09-03 23:50 ` (unknown), Matthew Garrett 2013-09-03 23:50 ` [PATCH V3 01/11] Add secure_modules() call Matthew Garrett 2013-09-04 0:45 ` James Morris 2013-09-04 0:45 ` James Morris 2013-09-05 2:14 ` joeyli 2013-09-05 2:14 ` joeyli 2013-09-03 23:50 ` [PATCH V3 02/11] PCI: Lock down BAR access when module security is enabled Matthew Garrett 2013-09-04 0:45 ` James Morris 2013-09-04 0:45 ` James Morris 2013-09-04 16:57 ` David Woodhouse 2013-09-04 16:57 ` David Woodhouse 2013-09-04 17:04 ` Matthew Garrett 2013-09-04 17:04 ` Matthew Garrett 2013-09-04 18:58 ` David Woodhouse 2013-09-04 19:01 ` Matthew Garrett 2013-09-04 19:01 ` Matthew Garrett 2013-09-04 19:31 ` David Woodhouse 2013-09-04 19:31 ` David Woodhouse 2013-09-03 23:50 ` [PATCH V3 03/11] x86: Lock down IO port " Matthew Garrett 2013-09-04 0:45 ` James Morris 2013-09-05 3:52 ` H. Peter Anvin 2013-09-05 3:52 ` H. Peter Anvin 2013-09-05 3:58 ` Matthew Garrett 2013-09-05 3:58 ` Matthew Garrett 2013-09-05 15:36 ` H. Peter Anvin 2013-09-05 15:36 ` H. Peter Anvin 2013-09-03 23:50 ` [PATCH V3 04/11] ACPI: Limit access to custom_method Matthew Garrett 2013-09-04 0:46 ` James Morris 2013-09-04 0:46 ` James Morris 2013-09-03 23:50 ` [PATCH V3 05/11] asus-wmi: Restrict debugfs interface when module loading is restricted Matthew Garrett 2013-09-04 0:46 ` James Morris 2013-09-04 0:46 ` James Morris 2013-09-03 23:50 ` [PATCH V3 06/11] Restrict /dev/mem and /dev/kmem " Matthew Garrett 2013-09-04 0:47 ` James Morris 2013-09-04 0:47 ` James Morris 2013-09-03 23:50 ` [PATCH V3 07/11] acpi: Ignore acpi_rsdp kernel parameter " Matthew Garrett 2013-09-03 23:50 ` Matthew Garrett 2013-09-03 23:50 ` [PATCH V3 08/11] kexec: Disable at runtime if the kernel enforces module loading restrictions Matthew Garrett 2013-09-04 0:48 ` James Morris 2013-09-04 0:48 ` James Morris 2013-09-04 20:09 ` jerry.hoemann 2013-09-04 20:09 ` jerry.hoemann-VXdhtT5mjnY 2013-09-04 20:12 ` Matthew Garrett 2013-09-04 20:12 ` Matthew Garrett 2013-09-04 20:12 ` Matthew Garrett 2013-09-04 20:14 ` Josh Boyer 2013-09-04 20:14 ` Josh Boyer 2013-09-04 20:14 ` Josh Boyer 2013-09-08 6:40 ` Greg KH 2013-09-08 6:40 ` Greg KH 2013-09-08 6:44 ` Matthew Garrett 2013-09-08 6:44 ` Matthew Garrett 2013-09-08 7:24 ` Greg KH 2013-09-08 7:24 ` Greg KH 2013-09-08 14:40 ` Matthew Garrett [this message] 2013-09-08 14:40 ` Matthew Garrett 2013-09-08 15:51 ` Kees Cook 2013-09-08 15:51 ` Kees Cook 2013-09-08 16:18 ` Greg KH 2013-09-08 16:18 ` Greg KH 2013-09-08 16:24 ` Matthew Garrett 2013-09-08 16:24 ` Matthew Garrett 2013-09-08 16:39 ` Greg KH 2013-09-08 16:39 ` Greg KH 2013-09-08 16:59 ` Matthew Garrett 2013-09-08 16:59 ` Matthew Garrett 2013-09-08 17:22 ` Greg KH 2013-09-08 17:22 ` Greg KH 2013-09-08 17:25 ` Matthew Garrett 2013-09-08 17:25 ` Matthew Garrett 2013-09-08 17:11 ` James Bottomley 2013-09-08 17:11 ` James Bottomley 2013-09-08 17:15 ` Matthew Garrett 2013-09-08 17:15 ` Matthew Garrett 2013-09-08 17:22 ` James Bottomley 2013-09-08 17:22 ` James Bottomley 2013-09-08 17:27 ` Matthew Garrett 2013-09-08 17:27 ` Matthew Garrett 2013-09-08 17:32 ` James Bottomley 2013-09-08 17:32 ` James Bottomley 2013-09-08 17:38 ` Matthew Garrett 2013-09-08 17:38 ` Matthew Garrett 2013-09-03 23:50 ` [PATCH V3 09/11] uswsusp: Disable when module loading is restricted Matthew Garrett 2013-09-04 0:48 ` James Morris 2013-09-04 0:48 ` James Morris 2013-09-05 3:20 ` joeyli 2013-09-05 3:20 ` joeyli 2013-09-03 23:50 ` [PATCH V3 10/11] x86: Restrict MSR access " Matthew Garrett 2013-09-04 0:49 ` James Morris 2013-09-04 0:49 ` James Morris 2013-09-03 23:50 ` [PATCH V3 11/11] Add option to automatically enforce module signatures when in Secure Boot mode Matthew Garrett 2013-09-03 23:50 ` Matthew Garrett 2013-09-04 1:42 ` James Morris 2013-09-04 1:42 ` James Morris 2013-09-04 1:42 ` Matthew Garrett 2013-09-04 1:42 ` Matthew Garrett 2013-09-05 3:13 ` joeyli 2013-09-05 8:24 ` joeyli 2013-09-05 8:24 ` joeyli 2013-09-05 10:16 ` Matt Fleming 2013-09-05 10:16 ` Matt Fleming 2013-09-05 12:54 ` Matthew Garrett 2013-09-05 12:54 ` Matthew Garrett 2013-09-04 15:53 ` Kees Cook 2013-09-04 15:53 ` Re: Kees Cook 2013-09-04 16:05 ` Re: Josh Boyer 2013-09-04 16:05 ` Re: Josh Boyer
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